Ability to output fixed file content to standard output

[fimtrey]

Is your feature request related to a problem? Please describe.
I'd like to better integrate vsg with vscode. I'm currently using the vscode task described in thread #531

But I'm sometimes continuing too soon, thus the formatter overrides the file while I've already made changes to the file, which the IDE cannot resolve. I'd thus like to integrate vsg into vscode as a formatter and not as a task.

There is an extension for vscode Custom Local Formatters which allows to call a local command, which could be vsg, but it needs the command to output the formatted file through stdout.

Describe the solution you'd like
A CLI option that forwards the fixed version of the file to the stdout instead of back to the file.

Describe alternatives you've considered
I'm currently using the task, described in the same thread.

Another option is to write my own formatter extension, but for this purpose I would again need an API which would not write to the file system directly. Thus, I think a versatile python API for vsg would also do the job for me but be more effort to develop.

A third option is to somehow circumvent this issue with a temporary file as pointed out here: #896. But I've haven't yet found a nice way of wrapping that around vsg in vscode.